Combination flyback curtain and snubber for ripsaw machines and the like

ABSTRACT

Downwardly biased relatively sharp-tipped fingers are pivotally mounted in a curtain row across the infeed end portion of a powered ripsaw machine table, with upper end shoulders on the fingers normally separably engaging a stop bar but permitting forward passage swinging of those fingers of which the tips are contacted by a piece of lumber during infeed.

United States Patent Inventor Lloyd George Alden, deceased late ofPlainlleld, III. by Verna R. Alden, executrix, 804 Barlett, Plainfield,I11. 60544,

Appl. No. 874,104

Filed Nov. 5, I969 Patented Dec. 14, 1971 COMBINATION FLYBACK CURTAINAND SNUBBER FOR RIPSAW MACHINES AND THE LIKE I I Claims, 4 Drawing Figs.

U.S. C1 143/159 C Int. Cl 827g 19/02 Field of Search 143/159 C,

[56] References Cited UNITED STATES PATENTS 1,681,832 8/1928 Wulf143/159 C 1,368,773 2/1921 Voss et a1. 143/159C 3.534,790 10/1970Thrasher 143/159 C Primary ExaminerDonald R. Schran An0rney Hill,Sherman, Meroni, Gross & Simpson ABSTRACT: Downwardly biased relativelysharp-tipped fingers are pivotally mounted in a curtain row across theinfeed end portion of a powered ripsaw machine table, with upper endshoulders on the fingers normally separably engaging a stop bar butpermitting forward passage swinging of those fingers of which the tipsare contacted by a piece of lumber during infeed.

Patented Dec. 14, 1971 3,62 @511 2 Sheets-Sheet 2 COMBINATION FLYBACKCURTAIN AND SNUBBER FUR RIPSAW MACHINES AND THE LIKE This inventionrelates to a safety device especially suitable for poweredripsawmachines and the like and is more particularly concerned with acombination flyback curtain and snubber device.

A problem encountered with production power machines adapted for actingon lumber, such as industrial ripsaw machines of the kind employed, forexample, in furniture factories to rip large pieces of lumber or timbersinto smaller pieces, resides in the liability of knots or other hardobstructions or foreign material such as nails to cause the saw bladesto eject the piece of lumber violently rearwardly and if the lumber isshattered for any reason to fling pieces rearwardly at dangerousvelocity. It is to meet this problem in a reliable and efficient mannerthat the present invention is directed.

An important object of the present invention is to provide a new andimproved safety device for the feed-in areas of power operated lumberprocessing machines such as ripsaws.

Another object of the invention is to provide a novel combinationflyback curtain and snubber device for ripsaw machines and the like.

Another object of the invention is to provide a new and improved,positively acting, highly reliable and efiicient safety finger array forproduction lumber processing machines such as ripsaws.

Other objects, features and advantages of the invention will be readilyapparent from the following description of certain preferred embodimentsthereof, taken in conjunction with the accompanying drawings, althoughvariations and modifications may be effected without departing from thespirit and scope of the novel concepts of the disclosure, and in which:

FIG. I is a perspective view of a ripsaw machine embodying featuresofthe present invention;

FIG. 2 is a fragmentary perspective view showing a front view of thesafety curtain and snubber;

FIG. 3 is an enlarged end elevational view of the safety curtain andsnubber device; and

FIG. 4 is a fragmental rear elevational view of the device.

By way of example of an important use for a combination flyback curtainand snubber 5 embodying features of the invention, a power ripsawmachine 7 is depicted in FIG. I. Such a machine includes a work table 8upwardly through which extend rotary ripsaw blades 9 cooperating withoverhead rotary ripsaws III. with feed-in rollers II acting on pieces oflumber fed in across the rear end portion of the table 8 to drive thepieces into the ripsaw blades to trim and subdivide the lumber pieceslongitudinally. Power may be supplied by an electrical motor I2 on themachine. Vertical adjustments of the table 8 may be effected through agearing system operated by a crank handle 113. On the table is mountedan adjustable lumber guiding bar 114.

Operation of the ripsaw blades 9 and I is effected at high speed andwith relatively high power input, depending, of course, upon the sizeand grade of lumber to be processed, to the extent that the motor 12 maybe rated up to as high as I00 horsepower. Consequently, a real hazardexists in the operation of the machine that ifa hard knot, nail or otherrelatively resistant area or matter is encountered by the saw blades apiece of lumber may be precipitately thrust rearwardly with considerableforce, or may even be shattered with pieces flung rearwardly withconsiderable velocity, in spite of and past the rearmost feed rollersII. It is to the elimination of this hazard that the present inventionis directed. To this end, the device comprises an array of pivotallymounted downwardly biased relatively sharp-ended antikickback safetyfingers I5 extending as a curtain row over and across the rear endportion ofthe table 8 in a manner to enable a piece or more of plankingor lumber, generally referred to herein as lumber L, to be fed freelyinto the machine (FIG, 2) but acting positively to prevent rearwardejection of the lumber as a piece or shattered pieces thereof.

Each of the fingers I5 is so constructed and arranged that it willafford maximum resistance to deformation in a front to rear directionwhile nevertheless permitting free passage of lumber of various widthswith unengaged fingers lying closely along one or both sides of thepiece of lumber so that there is minimum gap alongside the lumber. Tothis end, each of the fingers 15 is constructed as a relatively flatdownwardly tapered bar made of a suitable material such as steel, withthe finger plane extending in front to rear direction such that thebroad faces of the fingers are in confronting relation in the row. Attheir upper wider head end portions, considered in a front to reardirection, the fingers 15 are pivotally mounted on a shaft 17 withrelatively thin spacer washers I8 between the head end portions forcomplete freedom of relative pivotal swinging movement of the fingers onthe shaft. Along their rear edges the fingers are provided withrespective smooth downwardly and forwardly oblique cam surfaces nineteento facilitate passage of the leading end of a lumber piece intoengagement and past the engaged fingers. Further, construction of thefingers is such that the center of weight is forwardly from a verticallongitudinal plane through the shaft 17 whereby to assure downwardgravity bias of the fingers to depend from the shaft and to avoid thenecessity for biasing springs, although if preferred, biasing springscould be used. At their lower ends the fingers are provided withgenerally forwardly directed substantially chisel edges 20 adapted todig in and snubbingly retain the lumber piece L should it be thrustrearwardly. Efficiency of the chisel edges 20 is enhanced byintennediately notching out each of the edges as shown at 21 whereby tosubdivide each edge into two short edge sections (FIG. 4).

In order to .hold the fingers 15 against backing away from snubbingposition and to hold those fingers I5 which are serving as protectivecurtain against being swung rearwardly from safety curtain position,each of the fingers has on the upper rear portion of its head end a stopshoulder 22 which is separably engageable with a backup safety stop bar23 fixedly mounted on the shaft I7 over and across the head ends of thefingers. In order to facilitate assembly of the fingers and the washersI8 onto the shaft, the bar 23 is desirably mounted separably as by meansof spacer blocks 24 at the respective opposite end portions of the barseated on suitable respective flat milled seats 25 on the shaft andsecured by means of bolts 27 extending through the end portions of thebar and the spacer blocks 24 into tapped bores 28 in the shaft. Thearrangement is such that the stop bar 23 adequately overlies theshoulders 22 (FIG. 3) to provide positive step engagement therewith.

Mounting of the shaft I7 on the machine is desirably effected in amanner to enable preferred adjustment of the assembly to attain theutmost protective value from the fingers 115. To this end at least oneend portion of the shaft 17 is en gaged adjustably in a bracket 29comprising an elongated block having therein a bore 30 closely slidablyreceptive of an end portion of the shaft which is provided with ashallow annular groove 31 into which a setscrew 32 extending in from theadjacent end of the block 29 engages retainingly. Thereby adjustment ofthe shaft 17 rotatably is enabled in the block 29 as indicated indot-dash outline in FIG. 3. The groove 31 prevents interference withfree movement of the shaft into and out of the closely dimensioned bore30 should the setscrew 32 gouge the surface of the shaft engaged therebyin retaining the shaft in any preferred adjusted attitude of thesupported fingers and stop bar assembly. It will be appreciated that inFIG. 3 the relative illustrated range of positions of the shaft and iscarried assembly with respect to the bracket bar 29 have beensubstantially exaggerated for illustrative purposes and that inpractical sense the adjustments may be less in extent to meet optimumworking relationships.

Mounting of the bracket member 29 on the machine is desirably effectedin a manner to enable vertical adjustments of the finger assemblyrelative to the table 8. To this end, the bracket member 29 comprises asolid block which is horizontally intermediately slotted inwardly fromone end as shown at 33 such that by means of a bolt 34 the separatedforward end ortions of the bracket member are adapted to be clampedretainingly onto a stub shaft 35 rigid with the machine frame andprojecting through a suitable transverse bore 37 in the bracket bisectedby the slot 33. Through this arrangement, the bracket member 29 isadapted to be readily adjusted about the axis of the stub shaft 35substantially as indicated on comparison of the full line and dash linepositions of the bracket block and as demonstrated by the directionalarrows. in any adjusted position of the bracket 29, suitablecorresponding adjustment of the finger assembly is adapted to beeffected for optimum operating efficiency by relatively adjusting theshaft 17 in the bracket 29.

Where an unusually long row of the safety fingers 15 is necessaryandtherefore the supporting shaft and stop bar must also be correspondinglylong, another bracket 29 may be in supporting relation to the oppositeend of the shaft, rather than utilizing the cantilever arrangementdepicted which is adequate for relatively shorter rows of fingers.

In operation, after the safety finger assembly has been adjusted to anoptimum relation to the table 8 having regard to the thickness of lumberto be processed, a single or paired piece'of lumber L is thrustforwardly against the finger curtain, with those fingers engaged therebybeing swingably deflected, substantially as shown in FIG. 2. Beyond thefingers the leading end of the lumber is engaged by the first feedroller 1] and is then moved on forwardly through the machine. Should thesaws strike a knot or for some other reason exert a sufficientbackthrust on the lumber L to overcome the feed rollers 11, the chiseledges 20 of the fingers l engaging the lumber bite into the lumber andsimultaneously exert a downwardly snubbing thrust against the lumbertoward the table 8. Should the reverse or rearward ejection force on thelumber be sufficient to cause biting of the fingers down into theengaged lumber sufficiently to back the fingers to their rearward limit,the shoulders 22 of the fingers abut the stop bar 23 and furtherrearward swinging of the fingers is prevented so that the lumber pieceis positively held against rearward escape. Since the lumber is stillengaged by the feed rollers, they will normally resume feed of thelumber on through the saws unless whatever it is that caused rearwardejection movement of the lumber in the first instance will not permitfurther advance through the saws, in which case the operator of themachine will shut it down and withdraw the lumber. For highestefficiency,,the operating attitude of the safety fingers should be at asan acute an angle as practicable to the top surface of lumber fedthereby, with nevertheless ample leverage to assure thorough snubbingaction in the event ofa backthrust. By having the chisel edges normallyspaced above the table 8 and thus free from engagement therewith, theedges retain their sharpness and do not drop onto the table to cause anyroughness or gouging under any circumstance.

lclaim:

l. A combination fiyback curtain and snubber of the character described,comprising:

a shaft;

a row of antikickback safety fingers having upper end portions pivotallyengaged on said shaft with spacers between said upper end portions andthe fingers extending downwardly from the shaft and normally biased withsnubbing tips extending downwardly to engage freely upon a workpieceadvanced in one direction thereunder but operative to stop movement ofthe workpiece in the opposite direction;

each of said fingers having on the rear portion of the upper end portionthereof an upwardly facing stop shoulder; and

a stop bar carried by said shaft over said upper end portions of thefingers and releasably engageable by said stop shoulders to stoprearward swinging in maximum snubbing position of the fingers.

2; A combination according to claim 1, including means releasablyattaching said stop bar to said shaft.

3. A combination according to claim 1, including a bracket mounting oneend portion of said shaft rotatably, and means for securing the shaftfixedly in rotatably adjusted position with respect to the bracket.

4. A combination according to claim 3, including means supporting saidbracket and including means for adjusting the position of the bracketrelative to said bracket supporting means.

5. A combination according to claim 1, including opposite end spacerblocks on and between said bar and said shaft, and means securing saidbar and said spacer blocks to said shaft.

6. A combination according to claim 1, including a supporting bracketblock having a bore within which one end portion of said shaft isreceived, said end portion having a shallow annular groove therein, anda set screw carried by said bracket block and engaging said shaft insaid groove to secure the shaft in the bracket block.

7. A combination according to claim 6, said block being elongated andprojecting forwardly beyond said shaft end portion and having ahorizontal slot extending inwardly from the end remote from said shaft,the slotted end portion of the bracket block having a shaft boreintersecting said slot and adapted to receive a supporting shaft on amachine frame therethrough, and a securing bolt extending through theportions of the bracket block separated by said slot to clamp saidportions onto the supporting shaft.

8. A combination according to claim 1, including means for carrying saidshaft in cantilever fashion, and means for adjusting said carrying meansfor adjusting the vertical position of said shaft and thereby of saidfingers.

9. A combination according to claim 1, including means for supportingsaid shaft, and means for securing said shaft in pivotally adjustedrelation on said supporting means and thereby enable adjustment of saidstop bar by said pivotal adjustments of the shaft.

10. A combination according to claim 9, including means supporting saidshaft enabling vertical adjustments of the shaft and thereby of said barand said fingers.

11. A combination flyback curtain and snubber of the characterdescribed, comprising:

a row of fingers having snubbing tips at one end;

each of said fingers being of a downwardly tapered shape having an upperhead portion and said snubbing tips comprising substantially chiseledges directed generally downwardly and forwardly;

' said fingers having rear cam edges;

each of said fingers having on the upper head end portion a rearwardupwardly facing shoulder;

means relatively swingably supporting the fingers comprising a shaft onwhich the head end portions of the fingers are swingably mounted;

spacer washers between the head end portions of the fingers;

a stop bar overlying said fingers and releasably engageable by saidshoulders;

respective opposite end spacer blocks on and between said bar and saidshaft;

bolts securing said bar and said spacer blocks to said shaft;

a supporting bracket block having a bore within which one end portion ofthe shaft is received;

said end portion having a shallow annular groove therein;

a setscrew carried by said bracket block and engaging said shaft in saidgroove to secure the shaft in the bracket block;

said block being elongated and projecting forwardly beyond said shaftend portion and having a horizontal slot extending inwardly from the endremote from said shaft;

the slotted end portion of the bracket block having a shaft boreintersecting said slot and adapted to receive a supporting shaft on amachine frame therethrough; and

a securing bolt extending through the portions of the bracket blockseparated by said slot to clamp such portions onto the supporting shaft.

1. A combination flyback curtain and snubber of the character described,comprising: a shaft; a row of antikickback safety fingers having upperend portions pivotally engaged on said shaft with spacers between saidupper end portions and the fingers extending downwardly from the shaftand normally biased with snubbing tips extending downwardly to engagefreely upon a workpiece advanced in one direction thereunder butoperative to stop movement of the workpiece in the opposite direction;each of said fingers having on the rear portion of the upper end portionthereof an upwardly facing stop shoulder; and a stop bar carried by saidshaft over said upper end portions of the fingers and releasablyengageable by said stop shoulders to stop rearward swinging in maximumsnubbing position of the fingers.
 2. A combination according to claim 1,including means releasably attaching said stop bar to said shaft.
 3. Acombination according to claim 1, including a bracket mounting one endportion of said shaft rotatably, and means for securing the shaftfixedly in rotatably adjusted position with respect to the bracket.
 4. Acombination according to claim 3, including means supporting saidbracket and including means for adjusting the position of the bracketrelative to said bracket supporting means.
 5. A combination according toclaim 1, including opposite end spacer blocks on and between said barand said shaft, and means securing said bar and said spacer blocks tosaid shaft.
 6. A combination according to claim 1, including asupporting bracket block having a bore within which one end portion ofsaid shaft is received, said end portion having a shallow annular groovetherein, and a set screw carried by said bracket block and engaging saidshaft in said groove to secure the shaft in the bracket block.
 7. Acombination according to claim 6, said block being elongated andprojecting forwardly beyond said shaft end portion and having ahorizontal slot extending inwardly from the end remote from said shaft,the slotted end portion of the bracket block having a shaft boreintersecting said slot and adapted to receive a supporting shaft on amachine frame therethrough, and a securing bolt extending through theportions of the bracket block separated by said slot to clamp saidportions onto the supporting shaft.
 8. A combination according to claim1, including means for carrying said shaft in cantilever fashion, andmeans for adjusting said carrying means for adjusting the verticalposition of said shaft and thereby of said fingers.
 9. A combinationaccording to claim 1, including means for supporting said shaft, andmeans for securing said shaft in pivotally adjusted relation on saidsupporting means and thereby enable adjustment of said stop bar by saidpivotal adjustments of the shaft.
 10. A combination according to claim9, including means supporting said shaft enabling vertical adjustmentsof the shaft and thereby of said bar and said fingers.
 11. A combinationflyback curtain and snubber of the character described, comprising: arow of fingers having snubbing tips at one end; each of said fingersbeing of a downwardly tapered shape having an upper head portion andsaid snubbing tips comprising substantially chisel edges directedgenerally downwardly and forwardly; said fingers having rear cam edges;each of said fingers having on the upper head end portion a rearwardupwardly facing shoulder; means relatively swingably supporting thefingers comprising a shaft on which the head end portions of the fingersare swingably mounted; spacer washers between the head end portions oFthe fingers; a stop bar overlying said fingers and releasably engageableby said shoulders; respective opposite end spacer blocks on and betweensaid bar and said shaft; bolts securing said bar and said spacer blocksto said shaft; a supporting bracket block having a bore within which oneend portion of the shaft is received; said end portion having a shallowannular groove therein; a setscrew carried by said bracket block andengaging said shaft in said groove to secure the shaft in the bracketblock; said block being elongated and projecting forwardly beyond saidshaft end portion and having a horizontal slot extending inwardly fromthe end remote from said shaft; the slotted end portion of the bracketblock having a shaft bore intersecting said slot and adapted to receivea supporting shaft on a machine frame therethrough; and a securing boltextending through the portions of the bracket block separated by saidslot to clamp such portions onto the supporting shaft.